1. Field of the Invention
The present invention relates to smoke diluting devices, and more particularly to a mouthpiece for a cigarette, or the like, which reduces tar almost exclusively by ventilation.
2. Description of the Prior Art
It is well known in the art to add filters to cigarettes wherein the filters are provided with ventilating means to bring ambient air into the filter to dilute the smoke flowing through the filter. The dilution of the smoke reduces the quantity of smoke particulates as well as gas phase components which are delivered to the mouth of the smoker.
Another method for diluting the smoke is to make the tobacco column wrapper material permeable to air which allows for the introduction of air along the entire length of the tobacco column where it mixes with the smoke stream passing through the tobacco column thereby diluting the smoke.
Yet another method is to provide generally longitudinal ventilation air grooves in the periphery of a filter which grooves are open to the mouth end of the filter. The filtered smoke leaving the mouth end of the filter is mixed with the ventilation air exiting the ventilation air grooves in the smoker's mouth whereat the smoke is diluted. Examples of cigarette filters having grooves for the introduction of ventilating air into the filtering end are shown in the following patents: U.S. Pat. No. 3,577,995; U.S. Pat. No. 3,572,347; U.S. Pat. No. 3,490,461; U.S. Pat. No. 1,718,122; U.S. Pat. No. 3,788,330; U.S. Pat. No. 3,773,053; U.S. Pat. No. 3,752,165; U.S. Pat. No. 3,638,661; U.S. Pat. No. 3,608,561; U.S. Pat. No. 3,910,288; and U.S. Pat. No. 4,256,122.
It has also been proposed to provide a cigarette filter which delivers a combination of air diluted filtered smoke and undiluted, unfiltered smoke to the smoker's mouth. One such cigarette filter is shown in U.S. Pat. No. 3,860,011 as being formed of a hollow filter including a rigid non-deformable tube defining a smoke passage for delivering unfiltered smoke to the smoker's mouth, a concentric layer of filter material surrounding the tube, and a perforated outer wrap for the passage of air into the layer of filter material.
Devices for diluting unfiltered smoke with ventilating air before the smoke enters a smoker's mouth are also known. One example of such a device is shown in U.S. Pat. No. 3,552,399. The device, therein referred to as a filter for homogenizing air and smoke has a blind ended, longitudinal central axial passageway open to either the smoker's mouth or a filter element, a plurality of longitudinal passageways surrounding and extending parallel to the central passageway, and transverse passageways interconnecting the longitudinal passageways and central passageway with each other and with the ambient air. As the cigarette to which the device is smoked, smoke and ambient air traverses the longitudinal and central passageways wherein the smoke and air are mixed before delivery to the smoker's mouth.
Devices are also known for delivering unfiltered smoke and ventilation air to the smoker's mouth. For example, U.S. Pat. No. 4,023,576 teaches a cigarette with a hollow mouthpiece which defines a smoke chamber. The smoke chamber is separated from the tobacco column by two spaced apart baffle plates which define a curved path which the smoke must traverse before entering the smoke chamber. The mouth end of the chamber is closed by a wall having a central orifice for the flow of smoke out of the smoke chamber into the smoker's mouth. The exterior surface of the mouthpiece is provided with longitudinal grooves which cooperate with an overlaying perforated tipping paper to define flow paths for ventilating air. When a smoker draws on the mouthpiece, undiluted, unfiltered smoke is drawn from the tobacco column into the smoke chamber and through the outlet orifice centrally of the mouthpiece and into the smoker's mouth. At the same time, ventilation air is drawn in through the tipping paper and longitudinal grooves to mix with the undiluted smoke within the smoker's mouth.